Hello,
Thanks for your great plugin!
I am having the same problem.
I turned on everything in Quiz Settings>Marking and hit “save quiz” but when I navigate back to add more questions and then back to Quiz Settings>Marking, each of the selections has returned to the default off state.
I also tried just saving the markings without navigating away from the settings page and tested the quiz in separate (private) browser, but none of them will take. Do you have any suggestions?